<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../vue.js"></script>
</head>
<body>
    <h1>动态更新标签中内容</h1>
    <div id = "box">

    </div>
    <script>
        var obj = {}
        Object.defineProperty(obj,"username",{
            get(){
                console.log("get")
                return box.innerHTML
            },
            set(value){
                console.log("set",value)
                box.innerHTML = value
            }
        })
    </script>
</body>
</html>